Fibrous glass insulation products generally comprise matted glass fibers bonded together by a cured thermoset polymeric material. Molten streams of glass are drawn into fibers of random lengths and blown into a forming chamber where they are randomly deposited as a mat onto a traveling conveyor. The fibers, while in transit in the forming chamber and while still hot from the drawing operation, are sprayed with an aqueous binder. Formaldehyde-based binders are typically used. The residual heat from the glass fibers and the flow of air through the fibrous mat during the forming operation are generally sufficient to volatilize the majority to all of the water from the binder, thereby leaving the remaining components of the binder on the fibers as a viscous or semi-viscous high solids liquid. The coated fibrous mat is then transferred out of the forming chamber to a curing oven where heated air, for example, is blown through the mat to cure the binder and rigidly bond the glass fibers together.
Binders useful in fiberglass insulation products generally require a low viscosity in the uncured state, yet characteristics so as to form a rigid thermoset polymeric mat for the glass fibers when cured. A low binder viscosity, in the uncured state, is required to allow the mat to be sized correctly. Also, various binders tend to be tacky or sticky and hence they lead to accumulation of fibers on the forming chamber walls. This accumulated fiber may later fall onto the mat causing dense areas and product problems. A binder, which forms a rigid matrix when cured, is required so that a finished fiberglass thermal insulation product, when compressed for packaging and shipping, will recover to its specified vertical dimension when installed in a building.
Over the past several decades it has become necessary to minimize the emission of volatile organic compounds (VOCs) as a result of environmental regulations. This has led to extensive investigations into reducing emissions from formaldehyde-based binders, as well as searching for replacement binders that are formaldehyde-free. One such replacement binder employs polymers derived from acrylic acid.